Hospital bed caster apparatus

ABSTRACT

A caster apparatus is provided for a patient support. The caster apparatus includes a braking system.

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] This application claims the benefit of U.S. ProvisionalApplication Serial No. 60/317,271, filed Sep. 5, 2001, which isincorporated by reference herein.

[0002] This invention relates to hospital beds and more particularly tohospital beds having wheels or casters attached to a base frame forrolling the bed from location to location and a braking and steeringmechanism for controlling the casters.

[0003] Hospital beds are typically designed to be moved from location tolocation in a hospital or other health care facility. Therefore, bedshave wheels or casters which permit the hospital bed to be rolled andsteered between locations. During movement it is desirable to have freerolling wheels but upon reaching the desired location, brakes areusually applied to the wheels to maintain the bed at the desiredlocation.

[0004] It is well known to provide hospital beds with brake/steercasters which include mechanisms for blocking the rotation of thecasters, i.e. braking mechanisms, and mechanisms for blocking swivelingmovement of the caster fork, i.e. anti-swivel or directional locksteering mechanisms. Some beds with four castered wheels include pedalslocated on opposite sides of the bed which control the braking andanti-swivel mechanisms in each caster. Examples of such beds are shownin U.S. Pat. No. 5,377,372 and PCT Publication No. WO 00/51830 both ofwhich are incorporated herein by reference.

[0005] According to one embodiment of the present invention, a casterapparatus comprises a wheel having an axis of rotation, and a brakesystem including a brake member coupled to the wheel for rotation aboutthe axis of rotation of the wheel and a cable having a first end portioncoupled to the brake member and a second end portion. The apparatus alsocomprises an actuator coupled to the second end portion of the cable.The actuator is actuatable to move the cable, thereby rotating the brakemember about the axis of rotation to brake the wheel.

[0006] In one illustrated embodiment, the apparatus further comprises asleeve. The wheel is rotatably coupled to the sleeve and defines a firstsweep pattern as the wheel rotates relative to the sleeve. The brakemember defines a second sweep pattern as the wheel rotates relative tothe sleeve. The first sweep pattern is illustratively greater than orequal to the second sweep pattern.

[0007] According to another embodiment of the present invention, acaster apparatus comprises a wheel including a first side wall, a secondside wall, and an outer edge extending between the first and second sidewalls. The outer edge defines a circumference of the wheel, and thewheel is rotatable about an axis of rotation. The apparatus alsocomprises an external brake member coupled to the wheel adjacent thefirst side wall and within the circumference of the wheel, and anactuator coupled to the brake member. The actuator is actuatable tocause the brake member to prevent rotation of the wheel about the axisof rotation.

[0008] According to yet another embodiment of the present invention, apatient support apparatus comprises a patient support surface, a framecoupled to the patient support surface, and caster apparatus coupled tothe frame. The caster apparatus includes a wheel and a brake systemincluding an actuator, a cable, and a brake member. The cable has afirst end portion coupled to the actuator and a second end portioncoupled to the brake member. Actuation of the cable by the actuatorcausing the brake member to rotate about an axis to brake the wheel.

[0009] According to a further embodiment of the present invention, acaster apparatus comprises a wheel including a first side wall, a secondside wall, and an outer edge extending between the first and second sidewalls. The outer edge defines a circumference of the wheel. The wheel isrotatable about an axis of rotation. The apparatus also comprises abrake member coupled to the wheel. The brake member includes a plungermovable to brake the wheel. The plunger includes a brake surface locatedbelow the outer edge of the wheel. The apparatus further includes anactuator coupled to the brake member. The actuator is actuatable tobrake the wheel using vertical movement of the plunger and brake surfaceas the sole braking force on the wheel.

[0010] In one illustrated embodiment, the brake surface is a frictionbrake which engages an inner surface of the wheel located within thecircumference of the wheel to brake the wheel. In another illustratedembodiment, the brake surface is a friction brake which engages a floorwhen actuated by the actuator. In yet another illustrated embodiment,the wheel includes an inner surface having a plurality of teeth, and thebrake surface of the plunger also includes a plurality of teeth whichmate with the plurality of teeth on the inner surface of the wheel tobrake the wheel.

[0011] Additional features and advantages of the invention will becomeapparent to those skilled in the art upon consideration of the followingdetailed description of illustrated embodiments exemplifying the bestmode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The detailed description of the drawings particularly refers tothe accompanying figures in which:

[0013]FIG. 1 is a perspective view of a first embodiment of a casterapparatus including a rotation brake and a steer brake;

[0014]FIG. 2 is an end view of the caster apparatus of FIG. 1;

[0015]FIG. 3 is an overhead view of the caster apparatus of FIGS. 1 and2 showing a sweep of a wheel of the caster apparatus as the wheelrotates about a sleeve;

[0016]FIG. 4 is a cross sectional view of a prior art caster apparatus;

[0017]FIG. 5 is a cross sectional view of a second embodiment of acaster apparatus of the present invention;

[0018]FIG. 6 is an enlarged cross sectional view of brake/steermechanism of the caster apparatus of FIG. 5;

[0019]FIG. 7 is a cut away side elevation view of a third embodimentcaster apparatus;

[0020]FIG. 8 is cross sectional view of a plunger of the caster of FIG.7;

[0021]FIG. 9 is a side elevation view of an actuation rod of the casterof FIG. 7;

[0022]FIG. 10 is a side elevation view of a bias rod of the caster ofFIG. 7;

[0023]FIG. 11 is a cross sectional view of a sleeve of the caster ofFIG. 7;

[0024]FIG. 12 is a cross sectional view of an upper bushing of thecaster of FIG. 7;

[0025]FIG. 13 is a cross sectional view of a lower bushing of the casterof FIG. 7;

[0026]FIG. 14 is an overhead view of a steer stop plate of the caster ofFIG. 7;

[0027]FIG. 15 is a side elevation view of a large spring of the casterof FIG. 7;

[0028]FIG. 16 is a side elevation view of a small spring of the casterof FIG. 7;

[0029]FIG. 17 is a cross sectional view of the caster of FIG. 7 in anunbraked position; and

[0030]FIG. 18 is a cross sectional view of the caster of FIG. 7 in abraked position.

DETAILED DESCRIPTION OF THE DRAWINGS

[0031] Referring to the drawings, FIGS. 1-3 illustrate one embodiment ofa caster apparatus 10 of the present invention. The caster apparatus 10includes a support fork 12 having a central axle 14 on which a wheel orcaster 16 is mounted. A brake apparatus 18 is configured to selectivelyprevent rotation of caster 16 about an axis 15 of axle 14. Brakeassembly 18 is actuated by a control such as, for example, a cable 21,such as a Bowden cable, which illustratively includes an internal wire22 coupled to an actuator 23.

[0032] Illustratively, actuator 23 is a hand lever, a foot pedal, anelectrical actuator, or a mechanical actuator located on a bed or otherpatient support such as a stretcher or chair. Actuator 23 is configuredto move wire 22 when actuated by a caregiver.

[0033] Wire 22 is configured to move plate 24 toward plate 26 to applythe brake to caster 16. Plates 24, 26 each include a brake aperture 27.Brake apertures 27 are sized to allow a brake ring 29 to freely rotatetherethrough when in a first position, and to brake against the brakering 29 when in a second position. Illustratively, actuator 23 moveswire 22 in the direction of arrow 25 in FIGS. 1 and 2. Such movement ofwire 22 moves plate 24 toward plate 26 and into the second position,braking against the brake ring 29. Alternatively, movement of wire 22moves plate 24 toward plate 26 to apply a brake to axle 14 and therebyprevent rotation of caster 16. When actuator 23 is released, plates 24and 26 automatically move back to the position shown in FIGS. 1 and 2 torelease the brake.

[0034] In another embodiment, brake assembly 18 is also used to lockrotation of caster 16 and fork 12 about an axis 28 of sleeve 30. In thisembodiment, a brake component 32 is mounted adjacent a bearing 34. Brakecomponent 32 may be a cam type brake where the vertical axle of thecaster is not completely round but rather has surfaces to be selectivelyengaged by another surface or arm to brake rotation. Alternatively,brake component 32 can be a spring loaded arm that, when engaged, entersapertures in the vertical axle to thereby brake rotation.

[0035] Since the brake assembly 18 is mounted adjacent the caster 16,the height of sleeve 30 can be substantially reduced or sleeve 30 may beeliminated so that a bed frame 36 can be mounted close to caster 16.Therefore, the frame 36 can be positioned as close to the floor aspossible so that a patient support surface of the bed may be moved to avery low position to facilitate a patient getting into or out of the bedor other patient support.

[0036] When the caster 16 rotates around axis 28, a caster sweep patternis illustrated by line 38 in FIG. 3. No bed components may be mountedbelow frame 36 within the area defined by the sweep pattern 38. Thebrake assembly 18 may be mounted at any location on caster 16,preferably so that an outer dimension of brake assembly 18 asillustrated diagrammatically in FIG. 3 does not extend beyond the castersweep dimension 38. Therefore, brake 18 may be added to caster 16without taking up additional usable space underneath the bed frame 36.By mounting the brake 18 on the caster 16, the height of sleeve 30 canbe reduced or sleeve 30 can be eliminated from the caster mechanism sothat the bed or other patient support can be moved to a lower position.It is understood that other types of caster mounted braking assembliesmay be used in accordance with the present invention. It should also beappreciated that a cover (not pictured) may be used with the presentembodiment so that brake assembly 18 is not openly exposed.

[0037]FIG. 4 illustrates a prior art caster braking mechanism 50 whichincludes fork arms 52 for holding a caster 54. Bearings 56 permitrotation of the fork 52 and caster 54. An outer plug-in sleeve 58 issubstantially narrower than bearings 56 and extends upwardly a largedistance. This large sleeve 58 hampers efforts to reduce the height of apatient support on which the caster is mounted. The height of sleeve 58illustrated by dimension 60 is often up to four inches which is a largedistance when efforts are being made to reduce the overall height of thepatient support.

[0038] Another embodiment of the present invention is illustrated inFIGS. 5 and 6. The caster braking apparatus 70 includes a support 72coupled to a fork 74 which is coupled to a caster 76. Support 72 isrotatably coupled to an outer sleeve 78 by bearings 80. An internalbrake 82 is coupled to a pin 84 including an upper head 86. Pin 84passes through a central aperture 87 in a plate 88 which is locatedwithin a notch 79 in sleeve 78. Pin 84 also extends through a centralaperture 89 formed in spring member 90. Spring member 90 is configuredto engage head 86 to bias the pin 84 upwardly in the direction of arrow94. An end portion 91 of spring member 90 engages a top surface 93 ofplate 88. An internal spring 92 also biases the plate 88 upwardly in thedirection of arrow 94. An actuator rod 96 is coupled to a cam 98.Rotation of actuator rod 96 in the direction of arrow 100, typically bya foot pedal, causes movement of head 86, pin 84 and brake 82 downwardlyin the direction of arrow 102. Therefore, brake 82 engages an outer edgeof caster 76 to brake the caster.

[0039] As best shown in FIG. 6, plate 88 includes spaced apart tabs 104which are configured to enter complementary grooves or notches 106formed in support 72 when the pin 84 is moved downwardly in thedirection of arrow 102 by a first distance to block swiveling rotationof the support 72 and caster 76 about axis 75. Movement of the pin 84 asecond distance causes brake 82 to engage caster 76. Braking apparatus70 can be set so that braking occurs before swiveling is prevent byadjusting the spring constants of spring member 90 and spring 92. Inother words, the spring constants can be chosen so that initial downwardmovement of pin 84 compresses spring member 90 so that brake 82 engagescaster 76. Further movement of pin 84 compresses spring 92 so that tabs104 enger grooves 106 to prevent swiveling.

[0040] As illustrated in FIGS. 5 and 6, the sleeve 78 is wider than thebearings 80. By making the sleeve 78 wider, the overall height of thesleeve 78 is reduced compared to prior art sleeves. Therefore, when thesleeve 78 is coupled to a hospital bed frame 110 shown in FIG. 5, theoverall height of the bed frame is reduced. The distance from the ground112 to a bottom edge 114 of frame 110 for five inch caster 76 is 140millimeters. The frame thickness is illustratively 50.8 millimeters.Therefore, the distance from the ground 112 to a center line of actuator96 illustrated at location 116 is illustratively 165 millimeters.Further, the distance from the ground to the upper edge of the frame is190.8 millimeters. It is understood that other types of conventionalcaster brake/steer mechanisms may be used in the wider sleeve 78 of thepresent invention.

[0041] Another embodiment of the present invention is configured for usewith a dual wheel caster such as illustrated in U.S. Pat. Nos. 5,133,106and 5,139,116 which are incorporated herein by reference. As illustratedin FIG. 7, the caster apparatus 120 includes spaced apart first andsecond wheels 122 and a sleeve 124 extending into a central portionbetween the wheels 122. Rotation brake components 130 are located withinthe sleeve 124 below an upper bushing 126. An actuator 128 is used toactuate the rotation brake components 130 as well as steer brakecomponents 132. Illustratively, the rotation brake components 130 mayinclude a brake pad which engages an interior portion of wheels 122 orthe floor, a gear component which engages gears on wheels 122 to brakethe wheels 122, or other suitable braking mechanisms.

[0042]FIG. 11 shows a cross section of sleeve 124. Sleeve 124 ispreferably constructed from weldable steel. Sleeve 124 includes amulti-diameter plunger/steer axle bore 134 defined therein, a pluralityof plunger securing bores 136, and a steer lock pin 138. Illustratively,bore 134 includes a top portion 131, a central portion 133, and a lowerportion 135.

[0043]FIGS. 12 and 13 show cross sections of lower ring bushing 140 andupper ring bushing 126. The ring bushings 140, 126 each include aplunger bore 142, 143 respectively. Both bushings 126, 140 areillustratively constructed from bronze. Lower ring bushing 140 has abody with an outer surface 141 and a smaller diameter bottom end wall145. Lower ring bushing 140 is press fit into the bottom of plunger bore134 of sleeve 124 so that bottom end wall 145 is received within thelower portion 135 of bore 134. Upper ring bushing 126 is likewise pressfit into the top portion 131 of plunger bore 134.

[0044]FIG. 8 shows a cross section of a plunger/steer axle 144. Plunger144 includes a frame mount 146, a steer stop plate mount 148 beneathframe mount 146, an upper bushing interface section 150 beneath steerstop plate mount 148, an annular securing notch or groove 152, a lowerbushing interface section 154 below annular securing groove 152, anactuation rod bore 156 centrally and axially located within plunger 144,a bias rod bore 158 perpendicular to actuation rod bore 156 and locatedwithin steer stop plate mount 148, and a spring aperture 160 located atthe lower side of the intersection of actuation rod bore 156 and biasrod bore 158.

[0045]FIG. 14 shows a steer stop plate 162. Steer stop plate 162illustratively is a round substantially flat member that includes aplunger bore 164 and a plurality of steer lock apertures 166. Plungerbore 164 is sized to receive steer stop plate mount 148 of plunger 144therein. Notches 167 formed in plate 162 engaged tabs 189 on mount 148to prevent rotation of the plate 162 relative to the plunger 144.Notches 167 formed in plate 162 engage tabs 189 on mount 148 to preventrotation of the plate 162 relative to the plunger 144. Steer lockapertures 166 are sized and located to selectively receive steer lockpin 138 therein.

[0046]FIGS. 9 and 10 show an actuation rod 168 and a bias rod 170.Actuation rod 168 has a bias rod aperture 172 therein sized to fixedlyreceive bias rod 170 therein. Bias rod 170 is longer than the length ofbias rod bore 158. Large and small springs 174 and 176 are shown inFIGS. 15 and 16.

[0047] Assembled caster apparatus is shown in FIG. 17 in a non-actuatedposition. To achieve the assembled caster apparatus 120, the largespring 174 is first slipped over bottom end 178 of plunger 144 and movedupward until spring 174 is around steer stop plate mount 148 andabutting frame mount 146. Steer stop plate 162 is then likewise slippedover bottom end 178 of plunger 144 such that plunger 144 is withinplunger bore 164. Steer stop plate 162 is then moved upward and orientedsuch that it is around steer stop plate mount 148 and abutting largespring 174.

[0048] Small spring 176 is placed within spring aperture 160. Actuationrod 168 is then placed inside actuation rod bore 156 and spring 176 suchthat bias rod aperture 172 aligns with bias rod bore 158. Bias rod 170is then inserted into bias rod bore 158 and bias rod aperture 172 andfixed such that spring 176 is below bias rod 170 and steer stop plate162 is above bias rod 170. Once plunger 144 is so assembled, smallspring 176 abuts bias rod 170, bias rod 170 abuts steer stop plate 162,steer stop plate 162 abuts large spring 174, and large spring 174 abutsframe mount 146. Actuation rod 168 may travel vertically withinactuation rod bore 156 with the distance of the travel limited by theinterface of the bias rod 170 and the bias rod bore 158. Small spring176 is a stronger spring than large spring 174. Small spring 176 isenough stronger such that in a non-actuated state, small spring 176biases bias rod 170 and actuation rod 168 upwards, thereby biasing steerstop plate upwards and compressing large spring 174.

[0049] Assembled plunger 144 is then placed within plunger bores 142,134, and 142 of the upper ring bushing 126, sleeve 124, and lower ringbushing 140 respectively. When so placed, lower bushing interfacesection 154 abuts lower ring bushing 140, upper bushing interfacesection 150 abuts upper ring bushing 126, annular securing aperture 152is horizontally aligned with plunger securing bore 136, actuation rod168 extends out of the bottom of sleeve 124, and steer stop plate mount148 extends above sleeve 124. Posts 180 are then inserted into plungersecuring bores 136. Posts 180 fixedly engage the walls of securing bores136 and enter annular securing aperture 152, thereby preventing theremoval of plunger 144 while still allowing rotational motion of plunger144 relative to sleeve 124.

[0050]FIG. 18 shows the caster apparatus 120 of FIG. 17 in an actuatedposition. Actuator 128, preferably similar to actuator rod and cam 96,98 as shown in FIG. 5, is rotated to cause actuation rod 168 to lower.Lowering of actuation rod 168 causes bias rod 170 to likewise lower andcompress small spring 176. Compression of small spring 176 allows largespring 174 to downwardly bias steer stop plate 162. Steer stop plate 162then moves downwardly with bias rod 170 if a steer lock aperture 166 isvertically aligned with steer lock pin 138 thereby locking steerrotation of the caster apparatus. However, if a steer lock aperture 166is not vertically aligned with steer lock pin 138, steer lock pin abutsan underside of steer stop plate, bias rod 170 disengages from steerstop plate 162, and steer stop plate 162 remains at the height of thetop of steer lock pin 138. Further rotation of sleeve 124 relative toplunger 144 and attached steer stop plate 162 aligns a steer lockaperture 166 with steer lock pin 138 at which time the downward bias oflarge spring 174 pushes steer stop plate 162 down such that steer lockpin 138 is within one of the plurality of steer lock apertures, therebyarresting steer rotation. The frequency and location of steer lockapertures 166 ensures that the caster apparatus is prevented fromsubstantially rotating once actuation rod 168 is lowered.

[0051] Lowering of the actuation rod 168 also causes locking of wheel122 rotation. A lower end 182 of actuation rod 168 has a brake 184coupled thereto. Brake 184 preferably assumes one of the following threeembodiments. First embodiment brake 184 includes a brake block thatmoves vertically with actuation rod 168 to enmesh with teeth on aninside surface of wheels 122. Second embodiment brake 184 includes abrake block similar to internal brake 82 of FIGS. 5 and 6. However,brake block of second embodiment brake 184 moves vertically withactuation rod 168 to engage the inside surface of wheels 122 as opposedto the outer surface as shown in FIGS. 5 and 6. Third embodiment brake184 includes a brake block that moves vertically with actuation rod 168to frictionally engage the floor on which the wheels 122 are located.Third embodiment brake 184 requires a longer actuation rod 168 or longerbrake block than the previous two embodiments to be able to reach thefloor rather than a portion of the wheel.

[0052] Rotation of actuator 128 back to its original position allowssmall spring 176 to act upon bias rod 170 to push actuation rod 168upwards, thereby disengaging the brake block and steer stop plate 162.

[0053] Although the invention has been described in detail withreference to certain preferred embodiments, variations and modificationsexist within the scope and spirit of the present invention.

What is claimed is:
 1. A caster apparatus comprising: a wheel having anaxis of rotation; a brake system including a brake member coupled to thewheel for rotation about the axis of rotation of the wheel and a cablehaving a first end portion coupled to the brake member and a second endportion; and an actuator coupled to the second end portion of the cable,the actuator being actuatable to move the cable, thereby rotating thebrake member about the axis of rotation to brake the wheel.
 2. Thecaster apparatus of claim 1, wherein the brake member is positioned onan exterior surface of the wheel.
 3. The caster apparatus of claim 1,further comprising a sleeve, the wheel being rotatably coupled to thesleeve and defining a first sweep pattern as the wheel rotates relativeto the sleeve, the brake member defining a second sweep pattern as thewheel rotates relative to the sleeve, the first sweep pattern beinggreater than or equal to the second sweep pattern.
 4. The casterapparatus of claim 1, wherein a highest vertical point of the brakemember is located at a position lower than a highest vertical point ofthe wheel.
 5. The caster apparatus of claim 1, wherein the brake memberincludes a substantially flat plate.
 6. The caster apparatus of claim 5,wherein the brake system includes a support ring coupled to an exteriorsurface of the wheel, the brake member being coupled to the support ringfor pivotable movement relative to the support ring about the axis ofrotation.
 7. The caster apparatus of claim 1, wherein the brake memberhas a first position in which brake member permits rotation of the wheeland a second position in which the brake prevents rotation of the wheel,and wherein movement of the cable by the actuator moves the brake memberfrom the first position to the second position.
 8. The caster apparatusof claim 7, wherein an angular acceleration placed on the wheel in afirst direction urges the brake member toward the first position.
 9. Thecaster apparatus of claim 7, wherein the brake member is biased towardthe first position.
 10. The caster apparatus of claim 1, furthercomprising a sleeve, the wheel being rotatably coupled to the sleeve,and a steer brake which selectively prevents rotation of the wheelrelative to the sleeve, the steer brake being coupled to the cable. 11.A caster apparatus comprising: a wheel including a first side wall, asecond side wall, and an outer edge extending between the first andsecond side walls, the outer edge defining a circumference of the wheel,the wheel being rotatable about an axis of rotation; an external brakemember coupled to the wheel adjacent the first side wall and within thecircumference of the wheel; and an actuator coupled to the brake member,the actuator being actuatable to cause the brake member to preventrotation of the wheel about the axis of rotation.
 12. The casterapparatus of claim 11, further comprising a cable having a first endportion coupled to the brake member and a second end portion, theactuator being coupled to the second end portion of the cable, theactuator being actuatable to move the cable, thereby causing the brakemember to prevent rotation of the wheel.
 13. The caster apparatus ofclaim 11, wherein the brake member is coupled to the wheel for rotationabout the axis of rotation of the wheel, the actuator being actuatableto move the cable, thereby rotating the brake member about the axis ofrotation to brake the wheel.
 14. The caster apparatus of claim 11,further comprising a sleeve, the wheel being rotatably coupled to thesleeve and defining a first sweep pattern as the wheel rotates relativeto the sleeve, the brake member defining a second sweep pattern as thewheel rotates relative to the sleeve, the first sweep pattern beinggreater than or equal to the second sweep pattern.
 15. The casterapparatus of claim 11, further comprising a sleeve, the wheel beingrotatably coupled to the sleeve, and a steer brake which preventsrotation of the wheel relative to the sleeve, the steer brake beingcoupled to the actuator.
 16. The caster apparatus of claim 11, furthercomprising a support ring coupled to an exterior surface of the wheel,the brake member being coupled to the support ring for pivotablemovement relative to the support ring to brake the wheel.
 17. A patientsupport apparatus comprising: a patient support surface; a frame coupledto the patient support surface; and a caster apparatus coupled to theframe, the caster apparatus including a wheel and a brake systemincluding an actuator, a cable, and a brake member, the cable having afirst end portion coupled to the actuator and a second end portioncoupled to the brake member, actuation of the cable by the actuatorcausing the brake member to rotate about an axis to brake the wheel. 18.The apparatus of claim 17, wherein the brake member is positioned on anexterior surface of the wheel.
 19. The apparatus of claim 18, furthercomprising a sleeve coupled to the frame, the wheel being rotatablycoupled to the sleeve and defining a first sweep pattern as the wheelrotates relative to the sleeve, the brake member defining a second sweeppattern as the wheel rotates relative to the sleeve, the first sweeppattern being greater than or equal to the second sweep pattern.
 20. Theapparatus of claim 17, wherein a highest vertical point of the brakemember is located at a position lower than a highest vertical point ofthe wheel.
 21. The apparatus of claim 17, wherein the wheel includes afirst side wall, a second side wall, and an outer edge extending betweenthe first and second side walls, the outer edge defining a circumferenceof the wheel, the brake member being coupled to the wheel adjacent thefirst side wall and within the circumference of the wheel.
 22. A casterapparatus comprising: a wheel including a first side wall, a second sidewall, and an outer edge extending between the first and second sidewalls, the outer edge defining a circumference of the wheel, the wheelbeing rotatable about an axis of rotation; a brake member coupled to thewheel, the brake member including a plunger movable to brake the wheel,the plunger including a brake surface located below the outer edge ofthe wheel; and an actuator coupled to the brake member, the actuatorbeing actuatable to brake the wheel using vertical movement of theplunger and brake surface as the sole braking force on the wheel. 23.The caster apparatus of claim 22, wherein the brake surface is afriction brake.
 24. The caster apparatus of claim 23, wherein thefriction brake engages an inner surface of the wheel located within thecircumference of the wheel to brake the wheel.
 25. The caster apparatusof claim 23, wherein the friction brake engages a floor when actuated bythe actuator.
 26. The caster apparatus of claim 22, wherein the wheelincludes an inner surface having a plurality of teeth, the brake surfaceof the plunger also includes a plurality of teeth which mate with theplurality of teeth on the inner surface of the wheel to brake the wheel.